Different from customary analog contents, digital contents of music and so forth can be copied by a plural number of times without suffering from any deterioration of the quality. Therefore, in recent years, illegal distribution and exchange of contents which are not permitted by the owner of the copyright have been and are increasing together with the popularization of the Internet and increase of the speed and the capacity of PCs (Personal Computers) and so forth.
In order to prevent such illegal acts, a copyright management system which makes use of a DRM (Digital Rights Management) technique of restricting the distribution and utilization of contents is being popularized. In the copyright management system mentioned, it is a popular method that the number of copies of an original content is managed strictly to restrict illegal copying as proposed by the SDMI (Secure Digital Music Initiative) and so forth (refer to, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2003-296486)).
However, a copyright management system of such a type wherein the number of copies of an original content is managed strictly as described above adopts such a configuration that, when a content is to be copied, an apparatus of a user of the content (a content processing apparatus, a content reproduction apparatus or the like) is connected to a management server which manages the total number of copies such that copying of the content is permitted/inhibited by the management server. Therefore, not only the performance of apparatus of content users, the connection scheme of a plurality of apparatus and so forth are restricted, but also a copyright management process must be executed every time copying of a content is performed, which is inefficient. Accordingly, the degree of freedom in utilization of contents is low, and particularly to a legal content user (that is, a person who pays a reasonable equivalent to a content producer and utilizes a content within a range of private use), when a plurality of apparatus are utilized to share a content, the degree of freedom in design is low, which is inconvenient.
Furthermore, in order for a content user to utilize a content, it is necessary for the content user to register one, two or more apparatus owned by the content user in some registration, which is inconvenient also to the user.
The present invention has been made in view of the problem described above, and it is an object of the present invention to provide a novel and improved communication system, communication method, content management apparatus and computer program by which a plurality of apparatus owned by the user can be registered and cancelled efficiently.